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The Pittsburgh Healthy
Heart Project (PHHP)
The Pittsburgh Healthy
Heart Project (PHHP) is an ongoing prospective epidemiological study
designed to examine the role of psychosocial factors in the development
of early signs of cardiovascular disease. One of the important features
of this study involves its use of state-of-the art methods for assessing
mental stress and stress responding, including the use of electronic
diary ratings collected over the course of daily living, the use of
intensive interview methods for measurement of chronic stress, and the
use of a standardized task protocol for the measurement of
cardiovascular reactivity.
 Our
major outcome of interest in PHHP is a measure of artery wall thickness
used as an index of atherosclerosis, the lesion that causes heart
disease. This outcome measure, which is referred to as “intima-medial
thickness” or IMT, can be assessed in the large carotid arteries along
the neck using ultrasound techniques. Because atherosclerosis tends to
develop at a fairly uniform rate across different artery beds, measures
of carotid artery IMT have been shown to predict future development of
heart attack as well as stroke in community samples. Because carotid
artery IMT can be measured in asymptomatic adults who have no history of
heart disease, it is a good research measure for documenting early signs
of cardiovascular disease.
 One
of the additional features of this study involves the measurement of
ambulatory blood pressure. Ambulatory blood pressure (ABP), or blood
pressure taken during the course of daily life, has been shown to be a
better predictor of heart disease than blood pressure measures taken in
the doctor’s office in a number of studies. Previous studies have not
been able to determine whether this is due to differences in the
settings in which blood pressure is taken (daily life vs. office) or
whether this is due to differences in the number and type of readings
taken with ABP (typically, ABP involves a larger number of readings,
taken with an automated monitor whereas blood pressure in the doctor’s
office involves only a few readings taken with a manual measurement
method). We compared the two methods of blood pressure measurement in
the PHHP, and we found that ABP measures were better predictors of
carotid artery IMT when compared with blood pressure taken in the office
setting, even after differences in the number and type of readings were
controlled. These findings suggest that, method differences aside,
ambulatory blood pressure may be a better predictor of the condition of
the heart and arteries because it is a better reflection of daily life
demands—for example, ABP more accurately detects the effects of daily
activities and psychological stress. These results were published in the
Journal of Hypertension in 2002.
More recent results
from the PHHP study suggest, indeed, that daily experiences of stress,
as measured by electronic diary reports, are associated with elevations
in blood pressure throughout the day as well as with early signs of
cardiovascular disease (IMT). These findings were published in the
January, 2004 edition of the journal Health Psychology. The
results are important because they suggest that stress may be an
important factor in health even during early stages of cardiovascular
disease. The results also provide important new methods to measure the
effects of stress on health, and, in the future, they may lead to better
strategies of monitoring and changing our responses to daily stressors. |
